Switching Places
by WuHaoNi
Summary: Sherlock is an Army doctor. John is a consulting detective. Done for the sherlockbbcfic lj community kinkmeme.
1. Chapter 1

**Disclaimer: I do not own Sherlock.**

**Done for the sherlockbbcfic_kink meme community prompt: Sherlock is a army doctor. John is a criminologist/consulting detective/forensic scientist.**

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Mycroft calls it his rebellious phase, and predicts Sherlock will never make it through his first week of basic training. ('They don't allow illegal drugs in the RAMC. And you've never been very good at being team player, Sherlock.')

His mother weeps in a way that promises hysteria and liberal use of smelling salts. ('But you're a doctor, sweetheart, why do you need to get shot at?')

His father doesn't do anything because his father is dead.

But Sherlock rather thought that his father would've approved of the notion, because it would give him "discipline".

Sherlock shrugs it all off. He's going to be an army doctor soon.

* * *

John's parents panic when their son starts collecting fallen birds—not to heal, but to dissect. John sees a therapist for a couple of months before the therapist concludes that it's simply scientific curiosity that drove John to do it, and not a latent expression of sociopathy.

The bird interests him so much that he thinks about becoming a pathologist, before deciding that med school really isn't for him. He does his subject in chemistry, and fucks around a bit in a pharmaceutical company before getting _restless_.

John toys with the notion of joining the army, but discards the idea quickly. It's a pipe dream.

And then a crime occurs outside his flat. And he meets D.I. Lestrade.

What a random crazy happenstance.

John has always been smart. Not genius level, mind you, but of above-average intelligence. Someone who could put two and two together in a reliably quick fashion. His perchance for "experimenting" in uni had given him a fairly solid base of practical knowledge about a large variety of molecules.

They come around and question him in a routine exercise in procedure. John, who had offhandedly observed the scene from his flat window, greets the Detective Inspector politely, and David Anderson in as civil fashion as he can muster.

'Watson,' Anderson mutters, averting his eyes as quickly as possible.

Lestrade looks at him with more than a little curiosity. John is willing to bet that he has never seen his forensic scientist this antagonistic.

'I suppose you're here about the murder then,' John sighs.

'How'd you know it was a murder?' Lestrade asks. There is suspicion and a bit of wariness in his voice.

'Knew Dave from uni; did his subject in forensics, didn't he? Never one for friendly chats.' John gives his nothing-to-see-here smile.

'Logical,' Lestrade acknowledges. 'Let's talk about last night, 'round 16:30. Notice anything funny about the woman in the flat cross the way?'

'She had heart problems.'

'So you were friends?'

'No, I only met her just the once.'

Lestrade frowns. 'Then how—'

'Bloody hell, here he goes again.' Anderson rolls his eyes and gives John a disgusted look. 'It's fucking unnatural what he can do.'

'I'm not sure I catch your meaning,' Lestrade says, quirking an eyebrow. 'Can you explain, please?'

'She smelled very strongly of hawthorn. It's a distinct smell; very fishy.' John shrugs.

'Is that supposed to mean something?'

'Hawthorn is rumoured to treat heart problems.'

'But how'd you know what it smelled like?'

'Because I've worked with triethylamine before, and my prof said that TEA smells like hawthorn.'

'Right.' Lestrade nods, looking a trifle confused. 'That's an odd leap to make.'

'Unnatural,' Anderson says with a nod. John's oddness is confirmed for him.

'Useful,' Lestrade corrects him. 'And how did you not catch that? Let's go.'

'Have a good day,' John calls after him.

Lestrade comes back. 'Thanks, Watson. You know, you should give some thought to forensics yourself. Good mind.'

It turns out that the woman did indeed have heart problems; her lover had poisoned her with an excess of hawthorn extract.

The _rush_ of contributing to solving the crime gives John something that he hadn't realised was missing from his life. He goes round to a bookshop and picks up a few books on forensics.

He has a lot to read up on.

* * *

Sherlock isn't one for aphorisms, but he can see the usefulness of one by William Sherman.

"_War is hell"._

Sherlock is an excellent physician—competent, good under pressure, if easily irritated. He has terrible bedside manner—but then, that's to be expected. His mentor in medical school had advised him to never work with living patients, because he wouldn't win any popularity contests with his abrupt, abrasive personality.

He's not so much interested in connecting with the patient as he is in the puzzle. But his rate of solving medical mysteries is twice as high as his fellows, and his nimble fingers can suture a man in less time than it takes some blokes to pull on scrubs. He's innovative when it comes to treating wounds, and his focus is legendary—more so when bullets are flying past his face.

And so they see no sense in keeping him in the home front like Mycroft has ordered, and instead sends him to the front line where he can use his powers for good.

Seven months, two weeks and five days in, his convoy is hit with an IED, and Sherlock is invalided home with a busted shoulder and shrapnel in his thigh.

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'Civilian life is boring,' Sherlock grumbles from his armchair. He stares out the window intermittently between glaring at the hated wooden cane Mycroft had provided for him.

('The limp is psychosomatic.' 'Don't be a child, Sherlock. You can barely walk.')

The idiot therapist provided for him by the army, looks him over with an expression that is a mixture of irritation and pity. She doesn't much like him, but then again, the feeling is quite mutual. It's her duty to provide him mandatory mental health care, and he knows that she's just waiting to wash her hands of him. According to her, he can't begin to "heal" until he pushes past his numerous defence mechanisms.

'You miss combat, then,' she surmises.

She doesn't write down anything at all anymore. He has easily read every line she wrote—even when she switched to a cipher. Child's play, really.

'How else would you explain the tremor?' Sherlock snaps, holding his hand out in front of him. It still shakes with that infuriating display of weakness. He's convinced that if he would just go back to Afghanistan, it would simply vanish.

'You're convinced that you don't have PTSD,' she says, trying to look him in the eye.

'Obviously,' Sherlock sneers, fixing his gaze on the stain on the ceiling. 'Wherever did you receive your degree from?'

The timer on her phone rings in a disgustingly chirpy fashion, and Sherlock jumps a bit.

'We'll pick up from here next week,' she says, and he knows that she hadn't missed a thing.

'_If_ I show up,' Sherlock says cuttingly. He stands up with some difficulty, wrapping violinist fingers over the polished wood. 'I'm beginning to think my "recovery" would go much faster if someone competent was treating me.'

'Good day, Dr. Holmes,' the therapist says with a long-suffering sigh in her voice.

* * *

It's a gorgeous spring day out, but John doesn't notice anything because he's exhausted. The new couple next door has decided that their honeymoon is now every night, and John is treated to orgasmic moaning so loud that he can hear it through the wall. He has complained, but the couple hasn't done anything.

He needs a new flat, which means he needs a flatmate. His current one is just cheap enough for him to live alone, but anything else will most likely necessitate a second person to sign on. This doesn't bode well at all for John.

Friends at uni had commented on how John was 'a nice bloke and all, but I wouldn't want to live with you'.

Apparently kitchen science experiments bothered some people. Well, it wasn't like he stored body parts anywhere.

He meets Mike Stamford for the first time while he's in the process of looking over some samples as a favour to Lestrade, who considers John to be more of a meticulous scientist than Anderson. They chat a bit—just some small talk to be polite—John happens to mention that he's in the market for a flatmate.

It's just aimless conversation.

There's no way of knowing that what happens next will change his life.

* * *

Sherlock is limping through the park and yelling angrily at his cell phone. Mycroft is insisting that Sherlock come live with Mummy for the duration of his recovery, and that this stubborn streak of his is upsetting her even more than his war injury did.

He finally hangs up, disgusted with the whole affair. It is then that he finally hears his name being called.

'Sherlock? Sherlock Holmes!' The man on the park bench gets up and walks over to Sherlock, who has stopped.

He stares a bit stupidly at the man, wondering how exactly they're acquainted. He can't remember the man's name through the haze of anger in his head. And it's altogether possible that he has simply deleted the man's identity during his yearly "hard-drive" cleaning.

'Hello,' he says, dipping his head. He puts on his charming-and-confused smile. 'I'm sorry, but I can't recall your name.'

'We were in med school together. Mike Stamford? Ring any bells?' Mike looks at him hopefully.

Mike Stamford. Mediocre doctor. Friendly to everyone. Utterly forgettable, hence the reason Sherlock had forgotten him.

'Oh, yes. Mike,' Sherlock says. His lip curls a bit. 'Of course I remember _you_.'

'I heard you went to the army. How was it?'

Sherlock's eyebrow inched off his hairline. What an utterly insipid question. It didn't even dignify a response. But Mike was waiting with that sickeningly happy puppy-like expression, and Sherlock _had_ to acquiesce to normal human courtesy.

'I was shot,' he replies shortly, dipping his head to indicate the cane. It's not the truth, but it gives him a quicker exit out of the conversation.

'Oh, right,' Mike laughs.

'Well. Good-day,' Sherlock says, and he turns to leave.

'Wait! We should catch up a bit. Haven't seen you in ages, you know.'

'Haven't we just "caught up"?'

'Let me buy you a coffee,' Mike insists. 'You wait here.'

He pats the bench next to him.

'I really must be going,' Sherlock insists.

'Well, where are you staying? I'll walk you there,' Mike says. He stands up. 'You must've just gotten into town, yeah?'

'I did,' Sherlock says, limping away from Mike, who easily catches up to him. 'And I'm staying at a hotel at present.'

'Why?' Mike says, aghast. 'You're a war hero!'

'Heroes don't exist,' Sherlock says flatly.

The exertion of walking has caught up to him, and he is beginning to regret the decision to take a walk. He eyes the bench a few metres ahead and wonders if Mike will fuss over him if he decides to sit down.

'I don't mean to pry, Sherlock, I know how you like your privacy, but do you need a place to stay?'

'Surely you're not offering,' Sherlock says sardonically.

Mike laughs a bit nervously. 'I don't think the wife would be happy about that.'

'Indeed. I hardly make the ideal flatmate.'

Mike frowns a bit. 'You know, you were the second person to tell me that today?'

'Who was the first?'

* * *

John is bending over the microscope, still processing Lestrade's samples, when Mike Stamford enters the lab for the second time. He is not alone however; accompanying him is a tall man with short dark hair and a sleek wooden cane. The man stands straight with military bearing, and seems very curious to see John.

'John Watson,' Mike says grinning. 'I want you to meet Dr. Sherlock Holmes.'


	2. Chapter 2

**Disclaimer: I do not own Sherlock.**

**A/N: Thank you to everyone who reviewed Chapter 1. I really appreciate the reviews; they give me a better idea of how well my characterisations are and what people enjoy reading. Please do review!**

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'You're not part of forensics,' Sherlock observes.

He has a very posh public school accent, and John thinks about the limp more carefully now. The suit is tailored to his body, but his hair is cut short in a desultory fashion. Contradictions.

'No,' John says agreeably. 'I consult with the London Met.'

'I didn't know the police allowed civilian consultants.'

'I'm one of the first. Trial basis, you could say.'

'Did your subject in Chemistry, I see. Interesting that you'd choose such a menial position that barely pays your rent.'

'Well, I like the excitement,' John starts to say, but stops. 'How'd you—'

'You hold the pipet in an upright position, instead of tilting it sideways.'

'Well, yeah. If you tilt it sideways, you get all the shit in the pipet bulb.'

'That's part of the elementary skill set for a chemist. Forensics doesn't generally teach proper form.' Sherlock tilts his head. 'You're not curious about my leg?'

John ejects the pipet tip into a beaker and lays the pipet down on the counter. Clearly he's not going to be able to concentrate. 'I don't like to pry.'

'My convoy was attacked by insurgents in Afghanistan. An IED exploded.'

John nods. 'You were an army doctor, then.'

"Indeed. I should inform you that I frequently have insomnia and play the violin when I cannot sleep.'

'Oh.' John clears his throat. 'I see.'

'Those are things a potential flatmate should know, don't you think?' Sherlock gives a flat, reptilian smile.

'Flatmate?' John says weakly. He's not sure what to make of this strange man, and the confusion must show on his face because Mike Stamford steps forward in a conciliatory fashion.

'I remember what you said, John, about getting a new flat and needing a new flatmate and I thought…'

'Convenient,' Sherlock says. His mobile buzzes and an extreme look of annoyance passes on his face. 'I must go. Ring me when you've got the flat's address.'

'I don't have your number.'

Sherlock holds out his hands in an imperious fashion, and John after a moment's consideration, passes over his mobile. Sherlock turns it over in his hands, reading miles into the scuffmarks on Harry's gift.

'Consulting business doesn't pay much,' Sherlock observes, thumbs moving over the keyboard.

'Clients pay a nominal fee,' John says defensively.

'And you're not in it for the money anyway, so what does it matter to you if you take your older brother's hand me downs.'

John let out a little laugh. 'How do you know all of this?'

'I pay attention.' He hands back John's mobile. 'There's some business I must attend to.'

He exits the room, leaving John with a look of profound confusion and Mike smiles sympathetically.

'You should see him diagnose patients.'

* * *

_Address is 221A. John Watson_.

_221B. SH_

John looks at the response and sighs a little. He's barely known the man a day and already he can tell co-habitation will be difficult. God, the stubbornness…and the _arrogance_…

And yet.

His remarks had been fascinating, with the kind of thinking John had to work to cultivate. Useful to have in his line of work. Maybe he could use Sherlock's ability to—

Ridiculous. The man was a _doctor_, for God's sake, not the trained scientist John was. And how could Sherlock be expected to cope with the physical demands of pursuing suspects on an injured leg? Lestrade had already bent rules to allow John into crime scenes. Two civilians—albeit one ex-Army—was a little too much liability.

_221B has stairs, _John texts back.

_Fine_. _SH._

Then, _Do NOT need coddling. SH._

John sighs out loud Maybe he would no longer need to be thoughtful with Sherlock around

_We'll meet at 11:00 tomorrow. SH_.

John tries to think about his plans for tomorrow. The serial suicides were receiving quite a bit of press attention and he knew Lestrade would want all hands on deck—consultants included. A press conference had been scheduled for 1 PM, and if he met with Sherlock at 11, there would probably be enough time to show some solidarity…

_Was not asking. SH_.

Well. That was that.

John rubs at his eyes and looks around his tiny flat. Hopefully. 221B would be bigger.

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Sherlock's stepping out of a limo when John arrives the next morning. He shuts the door quickly, but not before John catches a glimpse of the woman inside. The car drives away, and John must once again revise his impression of Sherlock Holmes.

'Have your own chauffeur, do you?' John says, a half-hearted joke. He can't fathom why the man would need a to share a flat—let alone one in a rather dodgy part of London for someone with a clearly privileged background.

'Not mine,' Sherlock says, words precise and controlled.

He makes it clear that the subject is not to be brought up again.

John shrugs. Sherlock's entitled to his own secrets.

'Shall we?' Sherlock motions to the door, and John takes his meaning, rapping his knuckles loudly on the black painted wood.

'You must be my new lodgers!' says the woman who opens the door, a smile on her wrinkled face.

'I'm John Watson, and this is Sherlock Holmes.'

'_Doctor_ Sherlock Holmes,' Sherlock corrects, and John has to fight hard to repress a sigh. He should've known the man was the type to insist upon titles.

'Well, I'm Mrs. Hudson. Come in, come in.'

They step inside, and John looks over the faded wallpaper, noting a curious brown stain in the carpet.

'Goodness, will you be able to climb the stairs all right?' Mrs. Hudson says to Sherlock.

John makes a noise under his breath, which can either be interpreted as a cough or _I-told-you-so_. The way Sherlock glares at him means his point was clearly taken.

Sherlock allows John to go first because he doesn't want John to see the effort it takes for something so simple. No matter how often he tells himself that it's just in his head, the very real pain reminds him that it's still there. And yet there is no medically valid reason for his limp—no damage to the muscle tissue nor permanent nerve damage. It's galling, and Mycroft's insistent way of interfering in his affairs only makes the injury worse.

He has no susceptibility to trauma; the war had always kept him busy. There was no emotional wrenching to see one of his unit-mates get blown up because Sherlock was always able to detach himself to look at the wound with an eye for fixing it. There was no connecting with a patient on an emotional level—only making bodies whole again.

_Physician heal thyself_.

Some aphorisms are laughably untrue.


End file.
